The present invention relates to a ventilation system for a motor vehicle and more particularly to a mechanism for manual override of an automatically regulated ventilation system.
German Patent Application DE-Al-37 30 466 discloses a ventilation system for a motor vehicle that includes a regulating device to automatically regulate the distribution of temperature or air of an air stream through a plurality of outlet nozzles disposed in a dashboard or middle plane region of the vehicle.
The outlet nozzles in the middle plane (dashboard) of the vehicle serve above all the purpose of directly blowing cool air onto the vehicle occupants during a cooling operation. The blower speed, the air-distribution flaps, possibly the fresh air/circulated air flaps as well as the compressor and a water valve in a heat exchanger are automatically set by the regulating device, which is preferably electronic, in a closed control loop. The operational parameters are set according to a preselected program as a function of, on the one hand, a temperature setpoint which is able to be specified on a control unit in the dashboard and by various sensors, in particular by temperature sensors for the outside air, for the air exhaust in the main air chamber of the air conditioner on the output side, for the air inside the vehicle compartment, for the heat exchanger and the defogger as well as possibly by a sensor to detect the intensity of the actual values given off by received sunbeams. The adjustment of air-shut-off flaps, which are mounted in the air outlet nozzles of the middle plane, is thereby solely subject to the fully automatic regulation of the ventilation system. The direct flow of cold air from the outlet nozzles of the middle plane is generally considered pleasant by many vehicle occupants when outside temperatures, i.e., temperatures outside of the motor vehicle are high. However, the passenger may be subjected to uncomfortable drafts in the case of a fully automatic air conditioning system. This can occur due to the continued blowing of very cold air.